The present invention pertains to a stent for providing support to a vessel lumen of a living being and which includes a member normally lying against the stent inner wall but which is responsive to magnetic forces to thrash about within the lumen of the stent to maintain the lumen free of debris accumulation.
A variety of medical conditions in living beings requires the use of a device to expand and/or support a constricted vessel and to maintain an open passageway or lumen through the vessel. Examples of such conditions include holding a dissection in place, preventing closure during spasm and preventing acute vessel closure during or due to thrombosis.
Stents used to permit the flow of fluids in blocked vessels or ducts, such as arteries that are blocked by fatty deposits, may be made of plastic or metal materials. Stents may be maneuvered into narrowed areas of the biliary system of the liver to permit drainage of bile. Stents may also provide palliation by opening a channel in a duct or vessel. Accordingly, stents may replace or delay the need for surgical procedures to open or maintain a suitable passageway or lumen in a duct or vessel.
A major drawback of stents is the tendency for the passageway or lumen of the stent itself to become blocked with debris, such as fatty deposits. In these circumstances, stents need to be removed and replaced, if possible. In some instances, particularly involving stents made of metal mesh or in the form of a coil, the stent becomes so firmly anchored that it cannot be removed from the vessel or organ. Under such circumstances, surgical procedures may be necessary. The present invention is directed to overcoming the above-mentioned problem with the use of stents in various medical applications.
The present invention provides an improved stent for use in medical situations which require a device to expand and support a constricted vessel and/or to maintain an open lumen through the vessel of a living being.
In accordance with one aspect of the present invention, a stent is provided which includes one or more members adapted to thrash about within the passage or lumen of the stent to dislodge and break up any debris which may tend to accumulate in the stent so that the debris will move out of the lumen of the stent and prevent blockage of the stent. The movable member (or members) is preferably formed as a flexible wire normally biased to lie in engagement with the stent inner wall to minimize any obstruction in the stent lumen, which wire is responsive to magnetic forces to move about within the stent lumen to dislodge any material tending to accumulate within the stent lumen. The wire member is preferably disposed in a somewhat helical configuration lying against the stent inner wall and is secured at opposite ends to the stent and near opposite ends of the stent itself. The movable member or wire is responsive to magnetic forces, the direction of which may be altered to cause the wire to thrash about within the lumen of the stent.
In accordance with another aspect of the present invention, a method is providing for maintaining the lumen of an implanted stent substantially free of accumulated solids materials wherein magnetic forces are applied from the exterior of the body or organ in which the stent is disposed to cause a member forming part of the stent or disposed within the lumen of the stent to react to such magnetic forces to move about within the stent lumen to dislodge or prevent the accumulation of any solids materials within the stent lumen.
The method contemplates the provision of one or more electromagnets which may be disposed in a predetermined pattern external of the body of the being in which the stent is implanted. The electromagnet or electromagnets may be energized in such a way as to provide magnetic force fields which effect movement of the member within the stent to oscillate or thrash about within the stent lumen to dislodge any accumulated debris or solids materials in the stent lumen.
The improved stent and method in accordance with the invention substantially prolongs the life of a stent implanted within a living being by preventing the accumulation of solids materials within the stent lumen and without requiring invasive procedures to remove such solids materials.
Those skilled in the art will further appreciate the above-mentioned features and advantages of the invention together with other important aspects thereof upon reading the detailed description which follows in conjunction with the drawings.